Apparatus for producing fibers from thermoplastic material



N 1966 M. LEVECQUE ETAL 3,

APPARATUS FOR PRODUCING FIBERS FROM THERMOPLASTIC MATERIAL Original Filed Feb. 21, 1956 \9 L u H I\ INVENTORS M42054 ZE'l/ECQL/E Mmecez Mme/ea M4me/ce' ('HHEPE/V r/sz ATTORNEY United States Patent Claims. to]. 65-15) This application is a division of our application Serial No. 567,023, filed February 21, 1956, now Patent Number 3,1 14,618.

The present invention relates to the manufacture of fibers of mineral materials in the viscous state and particularly glass fibers.

It is already known, in order to produce fibers of great fineness, to subject the material projected under the action of centrifugal force to the action of gas currents discharging from a chamber fed by combustible and comburent and in which the combustion of these two elements is obtained. To accomplish this purpose a hollow body, whose surfaces are joined along a more or less sharp edge in which are located a single row of orifices, .is utilized,

the hollow body being surrounded by a combustion chamher taking the shape of an annular crown whose expansion orifice in the form of a continuous slot or a series of holes projects a ring-like blast of hot gases perpendicular to the plane of projection of the filaments from the orifices. A structure of this general type is shown in United States patent to Pierre Rene Heymes and Ivan Peyches No. 2,624,912, issued January 13, 1953. The described procedure and arrangement allows for an efiicacious drawing out of the filaments as soon as they leave the orifices, these filaments being drawn out and carried along with great force by the combustion gas escaping from the expansion orifice to form the fine fibers. However, because of the limited number of orifices provided on the peripheral edge of the rotating body, the fiber production of these arrangements is relatively low.

The present invention has for an object an improvement to the process and the arrangements noted above and permits a large and substantially uniform production of very fine fibers.

Conforming to the invention, the plastic material is projected at high temperature from a centrifugal body or element whose peripheral or filament delivery part, which can be notably of a cylindrical shape, bears a certain number of rows of projection orifices, one above the other, for example 2 to 20 rows. The filaments projected from the centrifugal body are subjected to the action of gases moving at high speed and high temperature escaping from the expansion orifices of an annular combustion chamber in such a manner as to effect, without the formation of either rigid or very viscous intermediary filaments, an entrainment of the filaments with an abrupt change in direction and an energetic attentuation and drawing out of the filaments so entrained, transforming them into very fine fibers. One might fear that the fact of providing two or more rows of projection orifices on the periphery of the centrifugal body might lead the fibers issuing from these orifices to stick and hinder the drawing out. Applicants have found that by distributing the projection orifices into several rows on the peripheral wall of the centrifugal body there is obtained a simultaneous drawing of the glass projected from these orifices, even if the orifices are lined up in the direction of the gas current. It has been possible, in fact, to observe exactly the different individual paths formed by the melted material projected from each orifice of the several rows of orifices.

Applicants have also found that the fibers thus formed can be drawn below the centrifugal body but may have .a tendency to regroup in the still plastic or hot state. This can result notably when the centrifugal body is surrounded by a combustion chamber having as expansion orifices, a continuous slot, or holes or slots very close together. In these circumstances there is formed below the centrifugal body a turbulent motion of air or gases which create a low pressure zone below the centrifugal body with a tendency to carry into that zone the hot gases from the combustion chamber and hence the fibers entrained therein.

This phenomenon can cause several serious drawbacks, especially the sticking of fibers under the centrifugal body and a sticking together of the. regrouped fibers and possibly collecting deformed filaments appearing as rigid and breaking small rods. These deficiencies are more noticeable as the number of orifices in the cenifiifugal body are increased and production of fibers enlarged.

One of the objects of the present invention is to correct .the above deficiencies, and provision is made for the direction of the fiber entraining and drawing (gaseous currents issuing from the combustion chamber in such a way as to restrain their movement toward the axis of the centrifugal body or even cause their movement away from said axis after the gaseous currents come int-o'contact with and entrain the filaments projected by the centrifuging body. This guidance of or control over the gaseous currents issuing from the combustion chamber may be effected by the use of air or gas currents or mechanical deflection elements located below the centrifugal body.

The present application is concerned with the provision 0If gaseous currents below the centrifugal body which impart a control upon the gaseous currents issuing from the combustion chamber so that the latter are guided away from below the center of the centrifugal body with the consequence that the fibers entrained thereby are prevented from re-grouping below said body.

Gas under pressure can be introduced within the interior of the ring of 'hot gases escaping from the annular combustion chamber at a suitable point below the centrifugal body. This compressed gas can be guided by nozzles, and delivered thereto by conduits passing through the centrifugal body or by a conduit passing across the ring of hot gases and fibers. This gas may be a combustible mixture which is ignited when it leaves the nozzles positioned below the centrifugal body. This gas will serve to restrain the hot gases and fibers therein from moving inwardly toward the axis of the centrifugal body or if desired, move them outwardly.

There can also be arranged below the centrifugal body a ring, exterior to oroutside of the currents of hot gases escaping from annular combustion chamber, provided neighboring orifices be about the same.

with orifices which discharge compressed gas to influence the direction of the hot gases from the combustion chamber and cause them to deflect outwardly with the entrained fibers or at least not toward the axis of the centrifugal body.

The drawings illustrate preferred embodiments of the invention wherein:

FIG. 1 is a fragmentary vertical section illustrating an annular nozzle discharging gas under pressure outwardly below the centrifugal body to influence and control the direction of the hot gases from the combustion chamber and the fibers entrained therein and drawn thereby;

FIG. 2 is a view, similar to FIG. 1, showing the annu lar nozzle supported and fed by a conduit extending across the line of attenuation of the fibers; and

FIG. 3 is a fragmentary vertical section through the centrifugal body and the combustion chamber showing an annular ring having nozzles delivering gases to induce the spread of the hot gases carrying the entrained fibers.

In the illustrated embodiments of the invention, a centrifugal body 1, rotating at high speed about its axis, through appropriate driving means at a speed of 3000 revolutions per minute or higher, carries at its peripheral part a cylindrical wall 1b bearing two to twenty rows of projection orifices 2 of suitable diameter, through which the molten material is projected at a temperature of about 1300 C.

It is advantageous for the orifices provided in the frontal peripheral wall of the centrifugal body to be separated in such a way that the distance separating the A suitable spacing of the orifices can be made by placing them according to regular quincuncial arrangements. A combustion chamber 3 of general annular shape is provided with an expansion orifice or orifices 4 which delivers the combustion gas at a very high speed and high temperature. The orifice 4 and the wall or walls defining the same are so positioned in respect to the peripheral wall 1b of the centrifugal body and the orifices contained therein that the molten material or filaments, as they are projected from the centrifugal body or at a slight distance therefrom are thrown into and picked up, entrained in and drawn by the hot gases passing across the peripheral surface of the centrifuge wall 1b and at an angle to the norm-a1 line of projection of the filaments from the centrifugal body. In the illustrated embodiments, this angle is approximately 90. These hot gases pass lightly over the peripheral wall of the centrifugal body and are in contact with all the projection orifices.

In the embodiments of the invention illustrated in FIGS. 1 and 2, compressed gases are introduced inside the ring of hot gases and the entrained fibers. As is shown in FIG. 1, a stationary tube 5, passing through the centrifugal body conducts compressed gas to nozzles 6. As shown in FIG. 2, tube 5a crosses the ring of hot gases to conduct compressed gas to nozzles 6. This tube is surrounded by an envelop 7, suitably streamlined and cooled, on which any deflected fibers can slide without being slowed down. As heretofore explained, the compressed gases issuing from the nozzles 6 of these embodiments serve to restrain any inward movement of the hot gases and the fibers entrained therein toward the axis of the centrifugal body and in fact may be used to guide or force the hot gases and fibers outwardly and away from the axis of the centrifugal body, in either case preventing a regrouping of the fibers while in the plastic state.

In the embodiment shown in FIG. 3, an annular ring is disposed below the centrifugal body and openings or nozzles 9 are provided therein for the discharge therethrough of a compressed gas which serves to induce the spreading of the hot gases and the entrained fibers. The nozzles 9 are directed downwardly and outwardly relative to the axis of the centrifuge, and by virtue of the positioning of the ring 10 beyond the peripheral wall of the centrifuge and the orifices 4 of the combustion chamber, the air currents issuingfrom the nozzles divert the fibers travelling from above in an outward direction.

In all forms of the invention, the centrifugal body will be heated internally by an appropriate burner or burners (not shown) so as to maintain the molten supply of material passing through the tube and into the interior of the centrifuge in a homogeneous state and at the proper centrifuging temperature.

Likewise, in all forms of the invention, the fibers projected from the orifices in the centrifugal body enter but do not pass through or beyond the hot gases issuing from the combustion chamber. Once the fibers enter the ring of hot gases or are picked up by those gases they are entrained therein and turned downwardly and attenuated and drawn into fine fibers by the travel and traction exerted by those gases. This end will be attained by appropriately adjusting or regulating the centrifugal force and the force of the hot gases issuing from the hot chamher.

We claim:

1. In apparatus for producing glass fibers from thermoplastic vitreous material, the combination of a centrifugal body having a peripheral wall provided with a plurality of superposed rows of orifices therein and adapted to receive at its interior portion a supply of the thermoplastic material in the viscous state, said body being rotatable at a speed sufficient to project the viscous material outwardly and uniformly through said orifices, a combustion chamber located adjacent said body and provided with a discharge opening having walls shaped to direct the discharge of gases from said chamber at high temperature and high velocity in a ring-like blast across said rows of orifices close to and in light contact with the peripheral wall of said body, said gases travelling at an angle to the plane of.rotation of said body whereby said streamlets of viscous material issuing from the orifices of the rotating body are turned, entrained and drawn out into an annular curtain of fine fibers by said gases, and blowing means having radially disposed openings therein positioned below said centrifugal body, for directing outwardly a gaseous medium at sufiicient velocity to act upon said fibers subsequent to their formation and initial attenuation, to divert said annular curtain of fibers from below the center of said centrifugal body.

2. An apparatus as set forth in claim 1 wherein said last-mentioned blowing means is supported by a fixed con- .duit extending coaxially of said centrifuge, said conduit also serving to feed the gaseous medium under pressure to said blowing means.

3. An apparatus as set forth in claim 1 wherein said last-mentioned blowing means is supported by a fixed conduit extending transversely of the axis of said centrifugal body and fiber-entraining gases, a cooled and streamlined envelope surrounding said conduit in the path of said annular curtain of fine fibers, said conduit also serving to feed the gaseous medium under pressure to said blowing means.

4. An apparatus as set forth in claim 1 wherein said last-mentioned blowing means comprises an annular ring below the centrifugal body surrounding said ring-like blast of high temperature and high velocity with the fibers entrained therein, with the openings in said ring being directed outwardly and downwardly.

5. In apparatus for producing glass-fibers from thermoplastic vitreous material, the combination of a centrifugal body having a peripheral wall provided with a plurality of superposed rows of orifices therein and adapted to receive at its interior portion a supply of the thermoplastic material in the viscous state, said body being rotatable at a speed sufficient to project the viscous material out-, wardly and uniformly through said orifices, a combustion chamber located adjacent said body and provided with a discharge opening having walls shaped to direct the .dis-

charge of gases from said chamber at high temperature and high velocity in a ring-like blast across said rows of orifices close to and in light contact with the peripheral wall of said body, said gases travelling at an angle to the plane of rotation of said body whereby said streamlets of viscous material issuing from the orifices of the rotating body are turned, entrained and drawn out into an annular curtain of fine fibers by said gases, and means below said centrifugal 'body communicating with a gas under pressure, said means being provided with a plurality of radially directed nozzles adapted to blow said compressed gases against the internal wall of said annular curtain to effect an outward movement thereof.

References Cited by the Examiner UNITED STATES PATENTS Re. 24,708 9/1959 Heymes et al. 656 5 2,609,566 9/1952 'Slayter et al. 65-14 X 2,931,422 4/1960 Long l82.5 X

FOREIGN PATENTS 1,124,489 2/1955 France.

10 DONALL H. SYLVESTER, Primary Examiner.

R. L. LINDSAY, Assistant Examiner. 

1. IN APPARATUS FOR PRODUCING GLASS FIBERS FROM THERMOPLASIC VITREOUS MATERIAL, THE COMBINATION OF A CENTRIFUGAL BOBY HAVING A PERIPHERAL WALL PROVIDED WITH A PLURALITY OF SUPERPOSED ROWS OF ORIFICES THEREIN AND ADAPTED TO RECEIVE AT ITS INTERIOR PORTION A SUPPLY OF THE THEROPLASTIC MATERIAL IN THE VISCOUS STATE, SAID BODY BEING ROTATABLE AT A SPEED SUFFICIENT TO PROJECT THE VISCOUS MATERIAL OUTWARDLY AND UNIFORMLY THROUGH SAID ORIFICES , A COMBUSTION CHAMBER LOCATED ADJACENT SAID BODY AND PROVIDED WITH A DISCHARGE OPENING HAVING WALLS SHAPED TO DIRECT THE DISCHARGE OF GASES FROM SAID CHAMBER AT HIGH TEMPERATURE AND HIGH VELOCITY IN A RING-LIKE BLAST ACROSS SAID ROWS OF ORIFICES CLOSE TO AND IN LIGHT CONTACT WITH THE PERPHERAL WALL OF SAID BODY, SAID GASES TRAVELLING AT AN ANGLE TO THE PLANE OF ROTATION OF SAID BODY WHEREBY SAID STREAMLETS OF VISCOUS MATERIAL ISSUING FROM THE ORIFICES OF THE ROTATING BODY ARE TRUNED, ENTRAINED AND DRAWN OUT INTO AN ANNULAR CURTAIN OF FINE FIBERS BY SAID GASES, AND BLOWING MEANS HAVING RADICALLY DISPOSED OPENINGS THEREIN POSITIONED BELOW SAID CENTRIFUGAL BODY, FOR DIRECTING OUTWARDLY A GASOUS MEDIUM AT SUFFICIENT VELOCITY TO ACT UPON SAID FIBERS SUBSEQUENT TO THEIR FORMATION AND INITIAL ATTENUATION, TO DIVERT SAID ANNULAR CURTAIN OF FIBERS FROM BELOW THE CENTER OF SAID CENTRIFUGAL BODY. 